ADDITION OF ERYTHROPOIETIN TO GRANULOCYTE-COLONY-STIMULATING FACTOR AFTER PRIMING CHEMOTHERAPY ENHANCES HEMATOPOIETIC PROGENITOR MOBILIZATION

Hemopoietic progenitor cell mobilization intended for autotransplantat ion is now feasible in many patients, following the administration of single cytokines (G-CSF, GM-CSF, IL-3) or their combination. Erythropo ietin (EPO) is a cytokine which showed an interesting activity also on non-erythroid progenitors, however the clinical relevance of this act ivity has not been sufficiently investigated yet. This retrospective s tudy has attempted to assess the effectiveness of the combination of E PO plus G-CSF after priming chemotherapy to increase the number of blo od progenitor cells, as compared to the results obtained by G-CSF alon e. Thirty-four patients underwent priming chemotherapy followed by cyt okine administration: 18 patients received G-CSF 5 mu g/kg/day and 16 patients G-CSF plus EPO 50 U/kg/day. The two groups were homogeneous a s regards the main clinical characteristics which are thought to affec t BPC mobilization. As for hemopoietic progenitor cell mobilization, w e observed that the combination of EPO and G-CSF was more effective in comparison,vith G-CSF alone, with a median of 1.9-fold for circulatin g MNC, 4.0-fold for CFU-GM, 4.7-fold for BFU-E and 2.8-fold increase f or CD34(+) cells. The results of apheresis collections revealed that t he same group of patients showed better results for total blood progen itor cells/kg. The difference was statistically significant both for B PC mobilization and collection. Our findings suggest that EPO has a sy nergistic activity with G-CSF in mobilizing hemopoietic progenitors; t he good results obtained, despite our pretreated patients, suggest tha t this cytokine combination has both biologic and clinical relevance.